The present invention relates to an elastic member for an ink jet recording apparatus, an ink tank and an ink jet recording apparatus, more specifically to an elastic member which is used as a sealing member for an ink tank valve and an ink tank in an ink tank used in an ink jet recording apparatus feeding a recording head with an ink to record printed letters on a printing medium, which is used as a sealing member for preventing an ink from leaking from a recording head in an ink jet recording apparatus body, which can be injection-molded by a two-color molding method and which comprises a material having an excellent durability, an ink tank using the same and an ink jet recording apparatus.